Field of the Invention
The present invention relates to an electronic circuit package and, more particularly, to an electronic circuit package provided with a composite shielding function having both an electromagnetic shielding function and a magnetic shielding function.
Description of Related Art
In recent years, an electronic device such as a smartphone is equipped with a high-performance radio communication circuit and a high-performance digital chip, and an operating frequency of a semiconductor IC used therein tends to increase. Further, adoption of an SIP (System-In Package) having a 2.5D or 3D structure, in which a plurality of semiconductor ICs are connected by a shortest wiring, is accelerated, and modularization of a power supply system is expected to accelerate. Further, an electronic circuit module having a large number of modulated electronic components (collective term of components, such as passive components (an inductor, a capacitor, a resistor, a filter, etc.), active components (a transistor, a diode, etc.), integrated circuit components (an semiconductor IC, etc.) and other components required for electronic circuit configuration) is expected to become more and more popular, and an electronic circuit package which is a collective term for the above SIP, electronic circuit module, and the like tends to be mounted in high density along with sophistication, miniaturization, and thinning of an electronic device such as a smartphone. However, this tendency poses a problem of malfunction and radio disturbance due to noise. The problem of malfunction and radio disturbance is difficult to be solved by conventional noise countermeasure techniques. Thus, recently, self-shielding of the electronic circuit package has become accelerated, and an electromagnetic shielding using a conductive paste or a plating or sputtering method has been proposed and put into practical use, and higher shielding characteristics are required in the future.
In order to realize the higher shielding characteristics, a composite shielding structure is proposed in recent years. The composite shielding structure has both an electromagnetic shielding function and a magnetic shielding function. In order to realize the composite shielding structure, it is necessary to form, in an electronic circuit package, an electromagnetic shielding by a conductive film (metal film) and a magnetic shielding by a magnetic film.
For example, the semiconductor package described in U.S. Patent Publication No. 2011/0304015 has a configuration in which a shield case (shield can) obtained by laminating a magnetic layer and a metal layer is bonded to a mold resin by adhesive. The semiconductor package described in U.S. Patent Publication No. 2013/0307128 has a configuration in which the surface of a mold resin is covered with a metal shield and a concave portion is formed in the mold resin so as to expose the upper surface of a semiconductor chip therethrough and then filled with a metal material or the like.
However, the configuration described in U.S. Patent Publication No. 2011/0304015 where an adhesive is used to bond the shield case is not only disadvantageous in terms of height reduction, but also makes it harder for the metal film to be connected to a ground pattern on a substrate. Further, the configuration described in U.S. Patent Publication No. 2013/0307128 where the concave portion formed in the mold resin is filled with a metal material or the like can enhance heat radiation performance; however, since it does not have a composite shield structure, shielding characteristics, especially in a low frequency region, are insufficient.